Warsaw is Poland's capital, rebuilt after 1944 with a UNESCO Old Town that looks historic and a skyline led by the Palace of Culture. The Royal Castle, Krakowskie Przedmieście, and Łazienki Park with Chopin's monument are the classic first day.
Along the Vistula, new boulevards and museums (including POLIN and the Uprising Museum) tell the 20th-century story. It is a full city, not a day-trip postcard: government, business, and a dense café culture. From Gdańsk it is the main long-distance domestic route.